Article inventory control (AIC) systems, in general, authorize, track, and control movement of a given article within a facility by a given user. An example is a library circulation control system. In this case, a user could identify himself or herself with an identification card containing magnetically or optically detectable data (e.g., a barcode). The articles, books in the collection of the library, typically would have a similar identifying label. Usually a computerized user database contains identification data on all registered patrons of the library, and a similar article database contains identification data on all books in the library. When someone desires to remove a book from the library, the library circulation control system will first verify that the person is an authorized patron of the library, i.e., that the person is authorized to check out any book, or any of a particular class of books. The system will then verify that the particular book may be removed from the library, e.g., that it is not "on reserve." If both the user and the book are authorized by the system, the book may be removed, ("checked out") by that user. This authorization is often a visual or audible signal to library personnel. Additionally, but not required, the system could maintain data which correlates the specific user with the specific books checked out, and may issue fine notices, usage reports, and the like.
To prevent unauthorized removal of articles by users of facilities, electronic article surveillance (EAS) systems may also be employed. An electronic article surveillance system is defined as a system which comprises:
(1) a remotely interrogatable marker attached to a given article; PA1 (2) means for interrogating and sensing the marker within an interrogation zone, thereby determining presence of the article; and PA1 (3) means for preventing removal of the article by a user of the facility. PA1 (a) an article inventory control system which responds to inputs including user identification data and article identification data to issue an article removal authorization signal, and PA1 (b) an electronic article surveillance system which controls removal of the article by detecting within an interrogation zone a sensitized electronically detectable marker secured to the article; PA1 (c) an article removal authorization signal receiver and PA1 (d) means responsive to the article removal authorization signal for initiating removal of the given article, comprising
For the purposes of this invention, the term "removal" is understood to include the ability of the user to gain access to an article, to move an article from one point to another within a facility, to bring an article into a facility, or to remove an article from a facility. The last of these is a common use of EAS systems. However, an EAS system as defined above can control, for example, the routing of articles from one portion of a factory assembly line to another.
Many EAS systems employ a magnetic "marker" attached to an article, with appropriate marker interrogation and sensing apparatus located at one or more locations in the facility. Typically, removal of an article is prevented by restricting movement of the article within or from the facility, as with a lockable exit gate. The gate is locked in response to an alarm signal when a marker is detected within an interrogation zone located immediately before the exit. In the library example used above, the marker may comprise a piece of magnetic material adapted to be inserted in the book spine or attached inside the book cover.
Typically, EAS systems employ permanently or reversibly deactivatable markers and the apparatus associated with them. Such markers are also known as "dual status" markers. Permanently deactivatable markers are preferred where it is appropriate in certain circumstances for an article to pass through the interrogation zone without preventing removal. For example, in a retail store, if an article of merchandise has been purchased in a particular department, the marker may be deactivated at that point so that an interrogation zone in another department will not activate the marker. Reactivatable markers are appropriate, for example, in libraries where patrons who check out a book for an extended period of time may subsequently visit the library with that book during that period. In this case, the system should not prevent subsequent removal of the book until the book has been returned, the marker reactivated, and the book returned to circulation.
Integration of the functions of the two systems described above into a single system is known in the art. For example, U.S. Pat. No. 3,665,449 (Elder et al.) at column 15, lines 62-67 generally suggests that automated library checkout systems may be combined with EAS systems. More specifically related to the present invention, U.S. Pat. No. 4,141,078 (Bridges, Jr. et al.) discloses an automated library circulation control system which provides for patron identification via a card reader, book identification via an optical reader, modification and interrogation of computer data files, an electromagnetic device for magnetizing and demagnetizing a magnetic strip in each book, detection of unauthorized removal of books from the library, and other functions. The disclosure of U.S. Pat. No. 4,141,078 (Bridges, Jr. et al.) is incorporated by reference into this application.
Application of this type of integrated system may be difficult, especially in libraries in which one or both of the individual systems are in current operation. For example, some existing EAS systems cannot distinguish individual markers, only whether a sensitized marker is present. Thus a single library might employ markers which are identical, even on different types of books in the collection. The marker therefore may not already contain coded inventory data which could identify the type of article to which it is attached. A library with such an EAS system in place, but no computerized inventory control system, would have to add a unique inventory control marker to each book. Each book generally must be uniquely identified, including the identification of multiple copies of a single title, some of which may be in general circulation while one is on reserve.
Furthermore, present EAS systems generally are not designed to receive removal authorization signals from AIC systems added later. Thus, for complete article removal control in such a facility, it is necessary to have separate article inventory control and article surveillance systems, and usually a manual, labor intensive, connection between the two. In a library, such a connection might be a circulation clerk who, seeing a flashing light on the AIC system indicating book removal authorization, physically passes a book through a marker deactivation device of the EAS system. Another possibility is for the circulation clerk to manually bypass the removal prevention means, e.g., physically passing the book around the interrogation device and handing the book to the patron on the other side of the lockable gate. Since the patron would pass through the interrogation zone without any marked books, the gate would remain unlocked and thus allow the patron to exit the library.